2 * Copyright (c) 2013-16, Stacey D. Son
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 #include <sys/cdefs.h>
28 #include <sys/param.h>
29 #include <sys/ctype.h>
31 #include <sys/fcntl.h>
32 #include <sys/imgact.h>
33 #include <sys/imgact_binmisc.h>
34 #include <sys/kernel.h>
36 #include <sys/malloc.h>
37 #include <sys/mutex.h>
38 #include <sys/namei.h>
40 #include <sys/sysctl.h>
42 #include <sys/vnode.h>
44 #include <machine/atomic.h>
47 * Miscellaneous binary interpreter image activator.
49 * If the given target executable's header matches 'xbe_magic' field in the
50 * 'interpreter_list' then it will use the user-level interpreter specified in
51 * the 'xbe_interpreter' field to execute the binary. The 'xbe_magic' field may
52 * be adjusted to a given offset using the value in the 'xbe_moffset' field
53 * and bits of the header may be masked using the 'xbe_mask' field. The
54 * 'interpreter_list' entries are managed using sysctl(3) as described in the
55 * <sys/imgact_binmisc.h> file.
59 * Node of the interpreter list.
61 typedef struct imgact_binmisc_entry {
62 SLIST_ENTRY(imgact_binmisc_entry) link;
66 uint8_t *ibe_interpreter;
67 struct vnode *ibe_interpreter_vnode;
68 ssize_t ibe_interp_offset;
69 uint32_t ibe_interp_argcnt;
70 uint32_t ibe_interp_length;
71 uint32_t ibe_argv0_cnt;
75 } imgact_binmisc_entry_t;
80 #define IBC_ADD 1 /* Add given entry. */
81 #define IBC_REMOVE 2 /* Remove entry for a given name. */
82 #define IBC_DISABLE 3 /* Disable entry for a given name. */
83 #define IBC_ENABLE 4 /* Enable entry for a given name. */
84 #define IBC_LOOKUP 5 /* Lookup and return entry for given name. */
85 #define IBC_LIST 6 /* Get a snapshot of the interpretor list. */
88 * Interpreter string macros.
90 * They all start with '#' followed by a single letter:
92 #define ISM_POUND '#' /* "##" is the escape sequence for single #. */
93 #define ISM_OLD_ARGV0 'a' /* "#a" is replaced with the old argv0. */
95 MALLOC_DEFINE(M_BINMISC, KMOD_NAME, "misc binary image activator");
97 /* The interpreter list. */
98 static SLIST_HEAD(, imgact_binmisc_entry) interpreter_list =
99 SLIST_HEAD_INITIALIZER(interpreter_list);
101 static int interp_list_entry_count;
103 static struct sx interp_list_sx;
105 #define INTERP_LIST_WLOCK() sx_xlock(&interp_list_sx)
106 #define INTERP_LIST_RLOCK() sx_slock(&interp_list_sx)
107 #define INTERP_LIST_WUNLOCK() sx_xunlock(&interp_list_sx)
108 #define INTERP_LIST_RUNLOCK() sx_sunlock(&interp_list_sx)
110 #define INTERP_LIST_LOCK_INIT() sx_init(&interp_list_sx, KMOD_NAME)
111 #define INTERP_LIST_LOCK_DESTROY() sx_destroy(&interp_list_sx)
113 #define INTERP_LIST_ASSERT_LOCKED() sx_assert(&interp_list_sx, SA_LOCKED)
116 * Populate the entry with the information about the interpreter.
119 imgact_binmisc_populate_interp(char *str, imgact_binmisc_entry_t *ibe, int flags)
121 uint32_t len = 0, argc = 1;
122 char t[IBE_INTERP_LEN_MAX];
125 memset(t, 0, sizeof(t));
128 * Normalize interpreter string. Replace white space between args with
132 while (*sp != '\0') {
133 if (*sp == ' ' || *sp == '\t') {
134 if (++len >= IBE_INTERP_LEN_MAX)
138 while (*sp == ' ' || *sp == '\t')
149 ibe->ibe_interpreter = malloc(len, M_BINMISC, M_WAITOK|M_ZERO);
151 /* Populate all the ibe fields for the interpreter. */
152 memcpy(ibe->ibe_interpreter, t, len);
153 ibe->ibe_interp_argcnt = argc;
154 ibe->ibe_interp_length = len;
156 ibe->ibe_interpreter_vnode = NULL;
157 if (flags & IBF_PRE_OPEN) {
162 while (*tp != '\0' && *tp != ' ') {
166 NDINIT(&nd, LOOKUP, FOLLOW | ISOPEN, UIO_SYSSPACE, t);
169 * If there is an error, just stop now and fall back
170 * to the non pre-open case where we lookup during
177 ibe->ibe_interpreter_vnode = nd.ni_vp;
182 * Allocate memory and populate a new entry for the interpreter table.
184 static imgact_binmisc_entry_t *
185 imgact_binmisc_new_entry(ximgact_binmisc_entry_t *xbe, ssize_t interp_offset,
188 imgact_binmisc_entry_t *ibe = NULL;
189 size_t namesz = min(strlen(xbe->xbe_name) + 1, IBE_NAME_MAX);
191 ibe = malloc(sizeof(*ibe), M_BINMISC, M_WAITOK|M_ZERO);
193 ibe->ibe_name = malloc(namesz, M_BINMISC, M_WAITOK|M_ZERO);
194 strlcpy(ibe->ibe_name, xbe->xbe_name, namesz);
196 imgact_binmisc_populate_interp(xbe->xbe_interpreter, ibe, xbe->xbe_flags);
198 ibe->ibe_magic = malloc(xbe->xbe_msize, M_BINMISC, M_WAITOK|M_ZERO);
199 memcpy(ibe->ibe_magic, xbe->xbe_magic, xbe->xbe_msize);
201 ibe->ibe_mask = malloc(xbe->xbe_msize, M_BINMISC, M_WAITOK|M_ZERO);
202 memcpy(ibe->ibe_mask, xbe->xbe_mask, xbe->xbe_msize);
204 ibe->ibe_moffset = xbe->xbe_moffset;
205 ibe->ibe_msize = xbe->xbe_msize;
206 ibe->ibe_flags = xbe->xbe_flags;
207 ibe->ibe_interp_offset = interp_offset;
208 ibe->ibe_argv0_cnt = argv0_cnt;
213 * Free the allocated memory for a given list item.
216 imgact_binmisc_destroy_entry(imgact_binmisc_entry_t *ibe)
221 free(ibe->ibe_magic, M_BINMISC);
223 free(ibe->ibe_mask, M_BINMISC);
224 if (ibe->ibe_interpreter)
225 free(ibe->ibe_interpreter, M_BINMISC);
227 free(ibe->ibe_name, M_BINMISC);
228 if (ibe->ibe_interpreter_vnode)
229 vrele(ibe->ibe_interpreter_vnode);
231 free(ibe, M_BINMISC);
235 * Find the interpreter in the list by the given name. Return NULL if not
238 static imgact_binmisc_entry_t *
239 imgact_binmisc_find_entry(char *name)
241 imgact_binmisc_entry_t *ibe;
243 INTERP_LIST_ASSERT_LOCKED();
245 SLIST_FOREACH(ibe, &interpreter_list, link) {
246 if (strncmp(name, ibe->ibe_name, IBE_NAME_MAX) == 0)
254 * Add the given interpreter if it doesn't already exist. Return EEXIST
255 * if the name already exist in the interpreter list.
258 imgact_binmisc_add_entry(ximgact_binmisc_entry_t *xbe)
260 imgact_binmisc_entry_t *ibe;
262 ssize_t interp_offset;
265 if (xbe->xbe_msize > IBE_MAGIC_MAX)
267 if (xbe->xbe_moffset + xbe->xbe_msize > IBE_MATCH_MAX)
270 for(cnt = 0, p = xbe->xbe_name; *p != 0; cnt++, p++)
271 if (cnt >= IBE_NAME_MAX || !isascii((int)*p))
274 for(cnt = 0, p = xbe->xbe_interpreter; *p != 0; cnt++, p++)
275 if (cnt >= IBE_INTERP_LEN_MAX || !isascii((int)*p))
278 /* Make sure we don't have any invalid #'s. */
279 p = xbe->xbe_interpreter;
282 while ((p = strchr(p, '#')) != NULL) {
297 /* Anything besides the above is invalid. */
303 * Preallocate a new entry. We do this without holding the
304 * lock to avoid lock-order problems if IBF_PRE_OPEN is
307 ibe = imgact_binmisc_new_entry(xbe, interp_offset, argv0_cnt);
310 if (imgact_binmisc_find_entry(xbe->xbe_name) != NULL) {
311 INTERP_LIST_WUNLOCK();
312 imgact_binmisc_destroy_entry(ibe);
316 SLIST_INSERT_HEAD(&interpreter_list, ibe, link);
317 interp_list_entry_count++;
318 INTERP_LIST_WUNLOCK();
324 * Remove the interpreter in the list with the given name. Return ENOENT
328 imgact_binmisc_remove_entry(char *name)
330 imgact_binmisc_entry_t *ibe;
333 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
334 INTERP_LIST_WUNLOCK();
337 SLIST_REMOVE(&interpreter_list, ibe, imgact_binmisc_entry, link);
338 interp_list_entry_count--;
339 INTERP_LIST_WUNLOCK();
341 imgact_binmisc_destroy_entry(ibe);
347 * Disable the interpreter in the list with the given name. Return ENOENT
351 imgact_binmisc_disable_entry(char *name)
353 imgact_binmisc_entry_t *ibe;
356 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
357 INTERP_LIST_WUNLOCK();
361 ibe->ibe_flags &= ~IBF_ENABLED;
362 INTERP_LIST_WUNLOCK();
368 * Enable the interpreter in the list with the given name. Return ENOENT
372 imgact_binmisc_enable_entry(char *name)
374 imgact_binmisc_entry_t *ibe;
377 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
378 INTERP_LIST_WUNLOCK();
382 ibe->ibe_flags |= IBF_ENABLED;
383 INTERP_LIST_WUNLOCK();
389 imgact_binmisc_populate_xbe(ximgact_binmisc_entry_t *xbe,
390 imgact_binmisc_entry_t *ibe)
394 INTERP_LIST_ASSERT_LOCKED();
395 memset(xbe, 0, sizeof(*xbe));
396 strlcpy(xbe->xbe_name, ibe->ibe_name, IBE_NAME_MAX);
398 /* Copy interpreter string. Replace NULL breaks with space. */
399 memcpy(xbe->xbe_interpreter, ibe->ibe_interpreter,
400 ibe->ibe_interp_length);
401 for(i = 0; i < (ibe->ibe_interp_length - 1); i++)
402 if (xbe->xbe_interpreter[i] == '\0')
403 xbe->xbe_interpreter[i] = ' ';
405 memcpy(xbe->xbe_magic, ibe->ibe_magic, ibe->ibe_msize);
406 memcpy(xbe->xbe_mask, ibe->ibe_mask, ibe->ibe_msize);
407 xbe->xbe_version = IBE_VERSION;
408 xbe->xbe_flags = ibe->ibe_flags;
409 xbe->xbe_moffset = ibe->ibe_moffset;
410 xbe->xbe_msize = ibe->ibe_msize;
416 * Retrieve the interpreter with the give name and populate the
417 * ximgact_binmisc_entry structure. Return ENOENT if not found.
420 imgact_binmisc_lookup_entry(char *name, ximgact_binmisc_entry_t *xbe)
422 imgact_binmisc_entry_t *ibe;
426 if ((ibe = imgact_binmisc_find_entry(name)) == NULL) {
427 INTERP_LIST_RUNLOCK();
431 error = imgact_binmisc_populate_xbe(xbe, ibe);
432 INTERP_LIST_RUNLOCK();
438 * Get a snapshot of all the interpreter entries in the list.
441 imgact_binmisc_get_all_entries(struct sysctl_req *req)
443 ximgact_binmisc_entry_t *xbe, *xbep;
444 imgact_binmisc_entry_t *ibe;
445 int error = 0, count;
448 count = interp_list_entry_count;
449 xbe = malloc(sizeof(*xbe) * count, M_BINMISC, M_WAITOK|M_ZERO);
452 SLIST_FOREACH(ibe, &interpreter_list, link) {
453 error = imgact_binmisc_populate_xbe(xbep++, ibe);
457 INTERP_LIST_RUNLOCK();
460 error = SYSCTL_OUT(req, xbe, sizeof(*xbe) * count);
462 free(xbe, M_BINMISC);
467 * sysctl() handler for munipulating interpretor table.
468 * Not MP safe (locked by sysctl).
471 sysctl_kern_binmisc(SYSCTL_HANDLER_ARGS)
473 ximgact_binmisc_entry_t xbe;
478 /* Add an entry. Limited to IBE_MAX_ENTRIES. */
479 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
482 if (IBE_VERSION != xbe.xbe_version)
484 if ((xbe.xbe_flags & ~IBF_VALID_UFLAGS) != 0)
486 if (interp_list_entry_count == IBE_MAX_ENTRIES)
488 error = imgact_binmisc_add_entry(&xbe);
492 /* Remove an entry. */
493 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
496 if (IBE_VERSION != xbe.xbe_version)
498 error = imgact_binmisc_remove_entry(xbe.xbe_name);
502 /* Disable an entry. */
503 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
506 if (IBE_VERSION != xbe.xbe_version)
508 error = imgact_binmisc_disable_entry(xbe.xbe_name);
512 /* Enable an entry. */
513 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
516 if (IBE_VERSION != xbe.xbe_version)
518 error = imgact_binmisc_enable_entry(xbe.xbe_name);
522 /* Lookup an entry. */
523 error = SYSCTL_IN(req, &xbe, sizeof(xbe));
526 if (IBE_VERSION != xbe.xbe_version)
528 error = imgact_binmisc_lookup_entry(xbe.xbe_name, &xbe);
530 error = SYSCTL_OUT(req, &xbe, sizeof(xbe));
534 /* Return a snapshot of the interpretor list. */
537 /* No pointer then just return the list size. */
538 error = SYSCTL_OUT(req, 0, interp_list_entry_count *
539 sizeof(ximgact_binmisc_entry_t));
545 error = imgact_binmisc_get_all_entries(req);
555 SYSCTL_NODE(_kern, OID_AUTO, binmisc, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
556 "Image activator for miscellaneous binaries");
558 SYSCTL_PROC(_kern_binmisc, OID_AUTO, add,
559 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_ADD,
560 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
561 "Add an activator entry");
563 SYSCTL_PROC(_kern_binmisc, OID_AUTO, remove,
564 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_REMOVE,
565 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
566 "Remove an activator entry");
568 SYSCTL_PROC(_kern_binmisc, OID_AUTO, disable,
569 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_DISABLE,
570 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
571 "Disable an activator entry");
573 SYSCTL_PROC(_kern_binmisc, OID_AUTO, enable,
574 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_WR, NULL, IBC_ENABLE,
575 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
576 "Enable an activator entry");
578 SYSCTL_PROC(_kern_binmisc, OID_AUTO, lookup,
579 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_RW|CTLFLAG_ANYBODY, NULL, IBC_LOOKUP,
580 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
581 "Lookup an activator entry");
583 SYSCTL_PROC(_kern_binmisc, OID_AUTO, list,
584 CTLFLAG_MPSAFE|CTLTYPE_STRUCT|CTLFLAG_RD|CTLFLAG_ANYBODY, NULL, IBC_LIST,
585 sysctl_kern_binmisc, "S,ximgact_binmisc_entry",
586 "Get snapshot of all the activator entries");
588 static imgact_binmisc_entry_t *
589 imgact_binmisc_find_interpreter(const char *image_header)
591 imgact_binmisc_entry_t *ibe;
596 INTERP_LIST_ASSERT_LOCKED();
598 SLIST_FOREACH(ibe, &interpreter_list, link) {
599 if (!(IBF_ENABLED & ibe->ibe_flags))
602 p = image_header + ibe->ibe_moffset;
604 if (IBF_USE_MASK & ibe->ibe_flags) {
605 /* Compare using mask. */
606 for (i = 0; i < sz; i++)
607 if ((*p++ ^ ibe->ibe_magic[i]) &
611 for (i = 0; i < sz; i++)
612 if (*p++ ^ ibe->ibe_magic[i])
615 if (i == ibe->ibe_msize)
622 imgact_binmisc_exec(struct image_params *imgp)
624 const char *image_header = imgp->image_header;
625 const char *fname = NULL;
630 size_t namelen, offset;
631 imgact_binmisc_entry_t *ibe;
637 /* Do we have an interpreter for the given image header? */
639 if ((ibe = imgact_binmisc_find_interpreter(image_header)) == NULL) {
644 /* No interpreter nesting allowed. */
645 if (imgp->interpreted & IMGACT_BINMISC) {
650 imgp->interpreted |= IMGACT_BINMISC;
653 * Don't bother with the overhead of putting fname together if we're not
656 if (ibe->ibe_argv0_cnt != 0) {
657 if (imgp->args->fname != NULL) {
658 fname = imgp->args->fname;
660 /* Use the fdescfs(5) path for fexecve(2). */
661 sname = sbuf_new_auto();
662 sbuf_printf(sname, "/dev/fd/%d", imgp->args->fd);
664 fname = sbuf_data(sname);
667 namelen = strlen(fname);
671 * We need to "push" the interpreter in the arg[] list. To do this,
672 * we first shift all the other values in the `begin_argv' area to
673 * provide the exact amount of room for the values added. Set up
674 * `offset' as the number of bytes to be added to the `begin_argv'
675 * area. ibe_interp_offset is the fixed offset from macros present in
676 * the interpreter string.
678 offset = ibe->ibe_interp_length + ibe->ibe_interp_offset;
680 /* Variable offset to be added from macros to the interpreter string. */
681 MPASS(ibe->ibe_argv0_cnt == 0 || namelen > 0);
682 offset += ibe->ibe_argv0_cnt * (namelen - 2);
684 /* Make room for the interpreter */
685 error = exec_args_adjust_args(imgp->args, 0, offset);
690 /* Add the new argument(s) in the count. */
691 imgp->args->argc += ibe->ibe_interp_argcnt;
694 * The original arg[] list has been shifted appropriately. Copy in
695 * the interpreter path.
697 s = ibe->ibe_interpreter;
698 d = imgp->args->begin_argv;
702 /* Handle "#" in interpreter string. */
706 /* "##": Replace with a single '#' */
710 /* "#a": Replace with old arg0 (fname). */
711 MPASS(ibe->ibe_argv0_cnt >= ++argv0_cnt);
712 memcpy(d, fname, namelen);
716 __assert_unreachable();
720 /* Replace space with NUL to separate arguments. */
731 /* Catch ibe->ibe_argv0_cnt counting more #a than we did. */
732 MPASS(ibe->ibe_argv0_cnt == argv0_cnt);
733 imgp->interpreter_name = imgp->args->begin_argv;
734 if (ibe->ibe_interpreter_vnode) {
735 imgp->interpreter_vp = ibe->ibe_interpreter_vnode;
736 vref(imgp->interpreter_vp);
740 INTERP_LIST_RUNLOCK();
747 imgact_binmisc_init(void *arg)
750 INTERP_LIST_LOCK_INIT();
754 imgact_binmisc_fini(void *arg)
756 imgact_binmisc_entry_t *ibe, *ibe_tmp;
758 /* Free all the interpreters. */
760 SLIST_FOREACH_SAFE(ibe, &interpreter_list, link, ibe_tmp) {
761 SLIST_REMOVE(&interpreter_list, ibe, imgact_binmisc_entry,
763 imgact_binmisc_destroy_entry(ibe);
765 INTERP_LIST_WUNLOCK();
767 INTERP_LIST_LOCK_DESTROY();
770 SYSINIT(imgact_binmisc, SI_SUB_EXEC, SI_ORDER_MIDDLE, imgact_binmisc_init,
772 SYSUNINIT(imgact_binmisc, SI_SUB_EXEC, SI_ORDER_MIDDLE, imgact_binmisc_fini,
776 * Tell kern_execve.c about it, with a little help from the linker.
778 static struct execsw imgact_binmisc_execsw = {
779 .ex_imgact = imgact_binmisc_exec,
782 EXEC_SET(imgact_binmisc, imgact_binmisc_execsw);